Irrigation system with ET based seasonal watering adjustment and soil moisture sensor shutoff

ABSTRACT

An irrigation system includes at least one environmental sensor, such as a solar radiation sensor that is installed on an irrigation site, and a soil moisture sensor that is also installed on the irrigation site. Programming allows an estimated ET value to be calculated based at least in part on the output signal of the environmental sensor. A pre-programmed watering schedule is automatically modified based on the estimated ET value to thereby conserve water while maintaining the health of plants on the irrigation site. The system automatically inhibits irrigation when an output signal of the soil moisture sensor indicates an amount of moisture in the soil is above a predetermined threshold.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57.

BACKGROUND

1. Field of the Invention

The present invention relates to residential and commercial irrigationsystems, and more particularly to irrigation controllers that useevapotranspiration (ET) data in calculating and executing wateringschedules.

2. Description of the Related Art

Electronic irrigation controllers have long been used on residential andcommercial sites to water turf and landscaping. They typically comprisea plastic housing that encloses circuitry including a processor thatexecutes a watering program. Watering schedules are typically manuallyentered or selected by a user with pushbutton and/or rotary controlswhile observing an LCD display. The processor turns a plurality ofsolenoid actuated valves ON and OFF with solid state switches inaccordance with the watering schedules that are carried out by thewatering program. The valves deliver water to sprinklers connected bysubterranean pipes. There is presently a large demand for conventionalirrigation controllers that are easy for users to set up in terms ofentering and modifying the watering schedules. One example is the Pro C®irrigation controller commercially available from Hunter Industries,Inc., the assignee of the subject application. The user simply entersthe start times for a selected watering schedule, assigns a station toone or more schedules, and sets each station to run a predeterminednumber of minutes to meet the irrigation needs of the site. The problemwith conventional irrigation controllers is that they are often set upto provide the maximum amount of irrigation required for the hottest anddriest season, and then either left that way for the whole year, or insome cases the watering schedules are modified once or twice per year bythe user. The result is that large amounts of water are wasted. Water isa precious natural resource and there is an increasing need to conservethe same.

In one type of prior art irrigation controller the run cycles times forindividual stations can be increased or decreased by pushing “more” and“less” watering buttons.

Another conventional irrigation controller of the type that is used inthe commercial market typically includes a seasonal adjustment feature.This feature is typically a simple global adjustment implemented by theuser that adjusts the overall watering as a percentage of the originallyscheduled cycle times. It is common for the seasonal adjustment to varybetween a range of about ten percent to about one hundred and fiftypercent of the scheduled watering. This is the simplest and most commonoverall watering adjustment that users of irrigation controllers caneffectuate. Users can move the amount of adjustment down to ten tothirty percent in the winter, depending on their local requirements.They may run the system at fifty percent during the spring or fallseasons, and then at one hundred percent for the summer. The ability toseasonally adjust up to one hundred and fifty percent of the scheduledwatering accommodates the occasional heat wave when turf and landscapingrequire significantly increased watering. The seasonal adjustmentfeature does not produce the optimum watering schedules because it doesnot take into consideration all of the ET factors such as soil type,plant type, slope, temperature, humidity, solar radiation, wind speed,etc. Instead, the seasonal adjustment feature simply adjusts thewatering schedules globally to run a longer or shorter period of timebased on the existing watering program. When the seasonal adjustmentfeature is re-set on a regular basis a substantial amount of water isconserved and while still providing adequate irrigation in a variety ofweather conditions. The problem is that most users forget about theseasonal adjustment feature and do not re-set it on a regular basis, soa considerable amount of water is still wasted, or turf and landscapingdie.

In the past, irrigation controllers used with turf and landscaping haveused ET data to calculate watering schedules based on actual weatherconditions. Irrigation controllers that utilize ET data are quitecumbersome to set up and use, and require knowledge of horticulture thatis lacking with most end users. The typical ET based irrigationcontroller requires the user to enter the following types ofinformation: soil type, soil infiltration rates, sprinkler precipitationrate, plant type, slope percentage, root zone depth, and plant maturity.The controller then receives information, either directly or indirectly,from a weather station that monitors weather conditions such as: amountof rainfall, humidity, hours of available sunlight, amount of solarradiation, temperature, and wind speed. The typical ET based irrigationcontroller then automatically calculates an appropriate wateringschedule that may change daily based on the weather conditions andindividual plant requirements. These changes typically include thenumber of minutes each irrigation station operates, the number of timesit operates per day (cycles), and the number of days between watering.All of these factors are important in achieving the optimum wateringschedules for maximum water conservation while maintaining the health ofturf and landscaping.

Another device that can be occasionally found connected to an irrigationcontroller is a soil moisture sensor. There are many methods used, butmost involve sensors containing spaced apart electrodes placed at rootzone depth in the soil to sense the moisture levels in the soil and helpcontrol irrigation amounts. There is typically a threshold set manuallyby the user to determine the “wet” and “dry” levels for the soil andplant conditions. However, systems with a standalone soil moisturesensor typically are used as a shutoff type device, and the sensor doesnothing to tell the controller how much or when to irrigate. Typicallythe homeowner or irrigation professionals must initially set up and thenadjust the irrigation periodically during the year to optimize theamount being applied.

While conventional ET based irrigation controllers help to conservewater and maintain plant health over a wide range of weather conditionsthey are complex and their set up is intimidating to many users. Theytypically require a locally mounted weather station having a complementof environmental sensors. Such locally mounted weather stations arecomplex, expensive and require frequent maintenance. Instead ofreceiving data from a locally mounted weather station, home owners andproperty owners can arrange for their ET based irrigation controllers toreceive weather data collected by a private company on a daily basis andtransmitted to the end user wirelessly, via phone lines or over anInternet connection. This reduces the user's up-front costs, andmaintenance challenges, but requires an ongoing subscription expense forthe life of the ET based irrigation controller. In addition, the usermust still have a substantial understanding of horticulture to set upthe ET based irrigation controller. For these reasons, most ET basedirrigation controllers are set up by irrigation professionals for a fee.These same irrigation professionals must be called back to the propertywhen changes need to be made, because the set up procedures are complexand not intuitive to most users. These challenges are limiting the saleand use of ET based irrigation controllers to a very small minority ofirrigation sites. This impairs water conservation efforts that wouldotherwise occur if ET based irrigation controllers were easier to set upand adjust.

SUMMARY

An irrigation system includes at least one environmental sensor, such asa solar radiation sensor, that is installed on an irrigation site, and asoil moisture sensor that is also installed on the irrigation site.Programming allows an estimated ET value to be calculated based at leastin part on the output signal of the environmental sensor. Apre-programmed watering schedule is automatically modified based on theestimated ET value to thereby conserve water while maintaining thehealth of plants on the irrigation site. The system automaticallyinhibits irrigation when an output signal of the soil moisture sensorindicates an amount of moisture in the soil is above a predeterminedthreshold.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified block diagram of an irrigation system inaccordance with an embodiment of the present invention.

FIG. 2 is a front elevation view of the stand alone irrigationcontroller of the system of FIG. 1 with its front door open to revealits removable face pack.

FIG. 3 is an enlarged perspective view of the back panel of the standalone irrigation controller of FIG. 2 illustrating one base module andone station module plugged into their respective receptacles in the backpanel.

FIG. 4 is a block diagram of the electronic portion of the stand aloneirrigation controller of FIG. 2.

FIG. 5 is a block diagram illustrating further details of the electronicportion of the stand alone irrigation controller of FIG. 2 that residesin the face pack of the controller.

FIG. 6 is a block diagram illustrating further details of the electronicportion of the stand alone irrigation controller of FIG. 2 that residesin the base module.

FIG. 7 is a block diagram illustrating further details of the electronicportion of the stand alone irrigation controller of FIG. 2 that residesin each of the station modules.

FIGS. 8A-8W are detailed flow diagrams illustrating the operation of thestand alone irrigation controller of FIG. 2.

FIG. 9 is a block diagram illustrating the electronic portion of the ETunit and sensors of FIG. 1.

FIG. 10 is a perspective view of the stand alone ET unit of the systemof FIG. 9.

FIG. 11 is a block diagram illustrating the electronic portion of thestand alone ET unit of FIG. 10.

FIGS. 12A-12E are flow diagrams illustrating the operation of the standalone ET unit of FIG. 9.

FIG. 13A is an enlarged vertical cross-section of the stand aloneweather station of the system of FIG. 1.

FIG. 13B is a fragmentary perspective view illustrating the springbiased arm of the stand alone weather station of FIG. 12A.

FIG. 14 is a block diagram illustrating the electronic portion of thestand alone weather station of FIG. 12.

FIG. 15 is a flow diagram illustrating the operation of the stand aloneweather station of FIG. 13A.

FIG. 16 is a block diagram of the electronic circuit connecting to thesoil moisture sensor.

FIG. 17 is a flow diagram illustrating the operation of the soilmoisture sensor.

FIG. 18 is a simplified block diagram of an alternate irrigation systemin accordance with a second embodiment of the present invention.

DETAILED DESCRIPTION

The entire disclosures of the following U.S. patents and U.S. patentapplications are hereby incorporated by reference: U.S. Pat. No.5,097,861 granted Mar. 24, 1992 of Hopkins et al. entitled IRRIGATIONMETHOD AND CONTROL SYSTEM; U.S. Pat. No. 5,444,611 granted Aug. 22, 1995of Peter J. Woytowitz, et al. entitled LAWN AND GARDEN IRRIGATIONCONTROLLER; U.S. Pat. No. 5,829,678 granted Nov. 3, 1998 of Richard E.Hunter et al. entitled SELF-CLEANING IRRIGATION REGULATOR VALVEAPPARATUS; U.S. Pat. No. 6,088,621 granted Jul. 11, 2000 also of PeterJ. Woytowitz et al. entitled PORTABLE APPARATUS FOR RAPID REPROGRAMMINGOF IRRIGATION CONTROLLERS; U.S. Pat. No. 6,721,630 granted Apr. 13, 2004also of Peter J. Woytowitz entitled EXPANDABLE IRRIGATION CONTROLLERWITH OPTIONAL HIGH-DENSITY STATION MODULE; U.S. Pat. No. 5,179,347granted Jan. 12, 1993 of Alfred J. Hawkins; U.S. Pat. No. 6,842,667granted Jan. 11, 2005 of Beutler et al. entitled POSITIVE STATION MODULELOCKING MECHANISM FOR EXPANDABLE IRRIGATION CONTROLLER; U.S. patentapplication Ser. No. 10/883,283 filed Jun. 30, 2004 also of Peter J.Woytowitz entitled HYBRID MODULAR/DECODER IRRIGATION CONTROLLER, nowU.S. Pat. No. 7,069,115 granted Jun. 27, 2007; pending U.S. patentapplication Ser. No. 10/985,425 filed Nov. 9, 2004 also of Peter J.Woytowitz et al. and entitled EVAPOTRANSPIRATION UNIT CONNECTABLE TOIRRIGATION CONTROLLER; pending U.S. patent application Ser. No.11/288,831 filed Nov. 29, 2005 of LaMonte D. Porter et al. and entitledEVAPOTRANSPIRATION UNIT FORRE-PROGRAMMING AN IRRIGATION CONTROLLER; U.S.patent application Ser. No. 11/045,527 filed Jan. 28, 2005 also of PeterJ. Woytowitz entitled DISTRIBUTED ARCHITECTURE IRRIGATION CONTROLLER,now U.S. Pat. No. 7,245,991 granted Jul. 17, 2007; U.S. Pat. No.7,289,886 of Peter J. Woytowitz granted Oct. 30, 2007 entitled MODULARIRRIGATION CONTROLLER WITH SEPARATE FIELD VALVE LINE WIRING TERMINALS;U.S. Pat. No. 7,225,058 of LaMonte D. Porter granted May 29, 2007entitled MODULAR IRRIGATION CONTROLLER WITH INDIRECTLY POWERED STATIONMODULES; pending U.S. patent application Ser. No. 11/458,551 filed Jul.19, 2006 of LaMonte D. Porter et al. entitled IRRIGATION CONTROLLER WITHINTERCHANGEABLE CONTROL PANEL; pending U.S. patent application Ser. No.12/042,301 filed Mar. 4, 2008 of Peter J. Woytowitz et al. entitledIRRIGATION CONTROLLER WITH SELECTABLE WATERING RESTRICTIONS; pendingU.S. patent application Ser. No. 12/181,894 filed Jul. 29, 2008 of PeterJ. Woytowitz et al. entitled IRRIGATION SYSTEM WITH ET BASED SEASONALWATERING ADJUSTMENT; and pending U.S. patent application Ser. No.12/251,179 filed Oct. 14, 2008 of Peter J. Woytowitz et al. entitledIRRIGATION SYSTEM WITH SOIL MOISTURE BASED SEASONAL WATERING ADJUSTMENT.The aforementioned U.S. patents and applications are all assigned toHunter Industries, Inc., the assignee of the subject application, exceptfor the patent granted Jan. 12, 1993 to Hawkins.

The present invention addresses the hesitancy or inability of users tolearn the horticultural factors required to set up a conventional ETbased irrigation controller. The irrigation system of the presentinvention has a familiar manner of entering, selecting and modifying itswatering schedules, and either built-in or add-on capability toautomatically modify its watering schedules based on ET data in order toconserve water and effectively irrigate vegetation throughout the yearas weather conditions vary. The user friendly irrigation system of thepresent invention is capable of achieving, for example, eighty-fivepercent of the maximum amounts of water that can theoretically beconserved on a given irrigation site, but is still able to be used bymost non-professionals. Therefore, a large percentage of users of theirrigation system of the present invention will have a much morebeneficial environmental impact than a near perfect solution provided bycomplex prior art ET based irrigation controllers that might at best beadopted a small percentage of users. Even within the small percentage ofusers that adopt the full ET device, many of them may not be set upcorrectly because of the complexities of ET, and may therefore operateinefficiently.

Referring to FIG. 1, in accordance with an embodiment of the presentinvention, an irrigation system 10 comprises a stand alone irrigationcontroller 12 connected via cable 14 to a stand alone ET unit 16 that isin turn connected via cable 18 to a stand alone weather station 20 andthe stand alone ET unit 16 that is also connected via cable 19 to astand alone soil moisture sensor 21. The controller 12 and ET unit 16would typically be mounted in a garage or other protected location,although they can have a waterproof construction that allows them to bemounted out of doors. The soil moisture sensor 21 is typically buried inthe ground in the irrigation area to be monitored for soil moisture at adepth determined by the plant root zone depth in the irrigation zone.The weather station 20 is typically mounted on an exterior wall, gutter,post or fence near the garage. The cables 14, 18 and 19 typicallyinclude copper wires so that power can be supplied to the ET 16 unit,the soil moisture sensor 21, and the weather station 20 from theirrigation controller 12. Data and commands are sent on other copperwires in the cables. Fiber optic cables can also be utilized for sendingdata and commands. In the event that wireless communications are usedwith any of the components, a battery may be used to power the wirelesscomponent. The controller 12, ET unit 16, soil moisture sensor 21, andweather station 20 may exchange data and commands via wirelesscommunication links 22, 26 and 24. A transformer 25 that plugs into astandard household 110 volt AC duplex outlet supplies twenty-four voltAC power to the stand alone irrigation controller 12. In its preferredform, the irrigation system 10 employs a hard wired communication link14 between the stand alone irrigation controller 12 and the stand aloneET unit 16 that are normally mounted adjacent one another, such as on agarage wall, a wireless communication link 26 between the stand alone ETunit 16 and the stand alone soil moisture sensor 21, and a wirelesscommunication link 24 between the stand alone ET unit 16 and the standalone weather station 20.

Referring to FIG. 2, the stand alone irrigation controller 12 may be thePro-C modular irrigation controller commercially available from HunterIndustries, Inc. The irrigation controller 12 includes a wall-mountableplastic housing structure in the form of a generally box-shaped frontdoor 26 hinged along one vertical edge to a generally box-shaped backpanel 28 (FIG. 3). A generally rectangular face pack 30 (FIG. 2) isremovably mounted over the back panel 28 and is normally concealed bythe front door 26 when not being accessed for programming. The face pack30 has an interface in the form of a plurality of manually actuablecontrols including a rotary knob switch 31 and push button switches 32a-32 g as well as slide switch 34 which serves as a sensor by-passswitch. Watering schedules consisting of various run and cycle times canbe entered by the user by manipulating the rotary knob switch 31 andselected ones of the push button switches 32 a-32 g in conjunction withobserving numbers, words and/or graphic symbols indicated on a liquidcrystal display (LCD) 36. Push buttons 32 c and 32 d are used toincrease or decrease the seasonal adjust value. The watering schedulescan be a complicated set of run time and cycle algorithms, or a portionthereof, such as a simple five minute cycle for a single station.Alternatively, existing pre-programmed watering schedules can beselected, such as selected zones every other day. Any or sub-combinationof manually actuable input devices such as rotary switches, dials, pushbuttons, slide switches, rocker switches, toggle switches, membraneswitches, track balls, conventional screens, touch screens, etc. may beused to provide an interface that enables a user to select and/or entera watering schedule. Still another alternative involves uploadingwatering schedules through the SMART PORT (Trademark) feature of theirrigation controller 12, more details of which are set forth in theaforementioned U.S. Pat. No. 6,088,621.

The face pack 30 (FIG. 2) encloses and supports a printed circuit board(not illustrated) with a processor for executing and implementing astored watering program. An electrical connection is made between theface pack 30 and the components in the back panel 28 through adetachable ribbon cable including a plurality of conductors 38 a-g (FIG.4). The circuitry inside the face pack 30 can be powered by a battery toallow a person to remove the face pack 30, un-plug the ribbon cable, andwalk around the lawn, garden area or golf course while entering wateringschedules or altering pre-existing watering schedules.

A processor 40 (FIG. 5) is mounted on the printed circuit board insidethe face pack 30. A watering program stored in a memory 42 is executableby the processor 40 to enable the processor to generate commands forselectively turning a plurality of solenoid actuated irrigation valves(not illustrated) ON and OFF in accordance with the selected or enteredwatering schedule. An example of such an irrigation valve is disclosedin U.S. Pat. No. 5,996,608 granted Dec. 7, 1999 of Richard E. Hunter etal. entitled DIAPHRAGM VALVE WITH FILTER SCREEN AND MOVEABLE WIPERELEMENT, the entire disclosure of which is hereby incorporated byreference. Said patent is also assigned to Hunter Industries, Inc.Typically the solenoid actuated valves are mounted in subterraneanplastic boxes (not illustrated) on the irrigated site.

The processor 40 communicates with removable modules 44 and 46 a-c (FIG.3) each containing a circuit that includes a plurality of solid stateswitches, such as triacs. These switches turn twenty-four volt ACcurrent ON and OFF to open and close corresponding solenoid actuatedvalves via connected to dedicated field valve wires and a common returnline to screw terminals 48 on the modules 44 and 46 a-c.

In FIG. 3, the modules 44 and 46 a are shown installed in side-by-sidefashion in station module receptacles formed in the back panel 28. Themodule 44 serves as a base module that can turn a master valve ON andOFF in addition to a plurality of separate station valves. Each moduleincludes an outer generally rectangular plastic housing with a slot atits forward end. A small printed circuit board (not illustrated) withinthe module housing supports the station module circuit that includesconductive traces that lead to the screw terminals 48 and to V-shapedspring-type electrical contacts (not illustrated) that are accessiblevia the slot in the forward end of the module housing. These V-shapedelectrical contacts register with corresponding flat electrical contactson the underside of a relatively large printed circuit board 49 (FIG. 4)mounted inside the back panel 28 when the module 44 is slid into itscorresponding receptacle. The relatively large printed circuit board 49is referred to as a “back plane.” The base module 44 and station modules46 a-c and the back plane 49 are thus electrically and mechanicallyconnected in releasable fashion through a so-called “card edge”connection scheme when the base module 44 and station modules 46 a-c areinserted or plugged into their respective receptacles.

An elongate locking bar 50 (FIG. 3) can be manually slid up and down inFIG. 4 between locked and unlocked positions to secure and un-secure themodules 44 and 46 a-c after they have been fully inserted into theirrespective receptacles. Opposing raised projections 52 formed on thelocking bar 50 facilitate sliding the locking bar 50 with a thumb. Apointer 54 extends from one of the raised projections 52 and serves as aposition indicator that aligns with LOCKED and UNLOCKED indicia (notillustrated) molded into the upper surface of another plastic supportstructure 56 mounted inside back panel 28.

The receptacles for the modules such as 44 and 46 a-c are partiallydefined by vertical walls 58 (FIG. 3) formed on the back panel 28.Vertical walls 60 also formed on the back panel 28 to provide support tothe modules 44. and 46 a-c. An auxiliary terminal strip providesadditional screw terminals 62 for connecting remote sensors andaccessories. The term “receptacles” should be broadly construed asdefined in one or more of the patents and pending applicationsincorporated by reference above.

FIGS. 4 and 5 are block diagrams of the electronic portion of the standalone irrigation controller 12. The electronic components are mounted onprinted circuit boards contained within the face pack 30, back panel 28,base module 44 and station modules 46 a-c. The processor 40 (FIG. 4) ismounted on the printed circuit board inside the face pack 30 andexecutes the watering program stored in the memory 42. By way ofexample, the processor 40 may be a Samsung S3F8289 processor thatexecutes a program stored in the separate memory 42 which can be anindustry standard designation Serial EEPROM 93AA6A non-volatile memorydevice. Alternatively, the processor 40 and memory 42 may be provided inthe form of a micro-computer with on-chip memory. The manually actuablecontrols 31, 32 a-32 g and 34 and the LCD display 36 of the face pack 30are connected to the processor 40. The processor 40 sends drive signalsthrough buffer 64 and back plane 49 to the base module 44. By way ofexample the buffer 64 may be an industry standard designation 74HC125device. The processor 40 sends data signals to the modules 46 a-cthrough buffer 66. The buffer 66 may be an H-bridge buffer includingindustry standard 2N3904/3906 discrete bipolar transistors.

The processor 40 (FIG. 4) controls the base module 44 and the stationmodules 46 a-c in accordance with one or more watering schedules. Serialor multiplexed communication is enabled via the back plane 49 to thebase module 44 and to each of the output modules 46 a-c. Suitablesynchronous serial data and asynchronous serial data station modulecircuits are disclosed in the aforementioned U.S. Pat. No. 6,721,630.The location of each module in terms of which receptacle it is pluggedinto is sensed using resistors on the back plane 49 and a comparator 68(FIG. 5) which may be an industry standard LM393 device. The face pack30 receives twenty-four volt AC power from the transformer 25 throughthe back plane 49 and, regulates the same via a power supply circuit 70(FIG. 5). The power supply circuit 70 includes a National SemiconductorLM7906 voltage regulator, a Microchip Technology MCPIOI-450 powersupervisor, and a Samsung KA431 voltage regulator. A lithium battery 72such as an industry standard CR2032 battery is included in the powersupply circuit 70 and provides backup power to the micro controller tomaintain the internal clock in the event of a power failure. The facepack ribbon cable 38 a-g (FIG. 4) that connects the face pack 30 and theback plane 49 can be disconnected, and a nine volt battery (FIG. 5) thensupplies power to the face pack 30. This allows a user to remove theface 30 pack from the back panel 28 and enter or modify wateringschedules as he or she walks around the irrigation site.

The modules 44 and 46 a-c have contacts 74 (FIG. 4) on the top sides oftheir outer plastic housings. When the modules are first plugged intotheir receptacles, only a communication path is established with theprocessor 40 via the back plane 49. At this time the locking bar 50(FIG. 3) is in its UNLOCKED position. Thereafter, when the locking baris slid to its LOCKED position finger-like contacts 76 (FIG. 4) on theunderside of the locking bar 50 register with the contacts 74 on thetops of the modules 44 and 46 a-c to supply twenty-four volt AC power tothe modules that is switched ON and OFF to the valves that are connectedto the modules. The finger-like contacts 76 are connected to a commonconductor 78 carried by the locking bar 50. When the locking bar 50 isslid to its LOCKED position projections and tabs that extend from thelocking bar 50 and the modules are aligned to prevent withdrawal of themodules. See the aforementioned U.S. Pat. No. 7,225,058 for furtherdetails.

FIG. 6 is a block diagram illustrating details of the electronic circuitof the base module 44. The base module circuit includes transistordrivers 80 and triacs 82 for switching the twenty-four volt AC signal ONand OFF to different solenoid actuated valves. By way of example, thetransistor drivers 80 may be industry standard 2N4403 transistors andthe triacs may be ST Microelectronics (Trademark) T410 triacs. Thetwenty-four volt AC signal is supplied to the triacs 82 via contact 74and line 83. The twenty-four volt AC signal from each of the triacs 82is routed through an inductor/MOV network 84 for surge suppression tofour field valve lines 86 a-d, each of which can be connected to acorresponding solenoid actuated valve. The valves are each connected toa valve common return line 88. The twenty-four volt AC signal is alsosupplied to a rectifier/filter circuit 90. The unregulated DC signalfrom the rectifier/filter circuit 90 is supplied to a NationalSemiconductor LM7905 voltage regulator 92 which supplies five volt DCpower to the face pack 30 via a conductor 38 c (FIG. 4) in the ribboncable.

FIG. 7 is a block diagram illustrating details of the electronic circuitin each of the station modules 46 a-c. The station module circuitincludes a microcontroller such as the Microchip (Trademark) PIC 12C508processor 94. The station module circuit further includes triacs 96 forswitching the twenty-four volt AC signal ON and OFF to three differentsolenoid actuated valves. The twenty-four volt AC signal is supplied tothe triacs 96 via contact 74 and line 98. The twenty-four volt AC signalfrom each of the triacs 94 is routed through an inductor/MOV network 98including Epcos Inc. S10K35 MOV's for surge suppression to three fieldvalve lines 100 a-c, each of which can be connected to a correspondingsolenoid actuated valve. The valves are each connected to the valvecommon return line 88. The twenty-four volt AC signal is also suppliedto a rectifier/filter circuit 90. The unregulated DC signal “from therectifier/filter circuit 102 is supplied to a National SemiconductorLM7905 voltage regulator 104 which supplies five volt DC power to themicrocontroller through a conductor (not illustrated).

FIGS. 8A-8W are detailed flow diagrams illustrating the operation of thestand alone irrigation controller 12 of FIG. 2. Those skilled in the artof designing and programming irrigation controllers for residential andcommercial applications will readily understand the logical flow andalgorithms that permit the processor 40 to execute the watering programstored in the memory 42. This watering program enables the processor 40to generate commands for selectively turning the plurality of valves ONand OFF in accordance with the selected or entered watering schedules.The watering program includes a seasonal adjustment feature thatprovides the capability for automatically modifying the wateringschedules to thereby conserve water while maintaining plant health. Byactuating one of the push buttons 32 c or 32 d the user can increase ordecrease the run types for all stations by a selected scaling factor,such as ten percent, to account for seasonal variations in temperatureand rainfall.

Referring to FIG. 10, the stand alone ET unit 16 includes a rectangularouter plastic housing 106 enclosing a printed circuit board (notillustrated) which supports the electronic circuit of the ET unit 16that is illustrated in the block diagram of FIG. 11. A microcontroller108 such as a Microchip PIC 18F65J90 processor executes firmwareprogramming stored internally in the microcontroller 108 and can accessexternal memory 110 such as an industry standard 93AA66A EEPROM memory.The microcontroller 108 can receive DC power from a lithium battery 112such as an industry standard CR2032 battery, which allows accurate timekeeping in the event of a power failure. Insulating strip 113 (FIG. 10)must be manually pulled out to establish an operative connection of thebattery 112. External power for the ET unit 16 is supplied from thetransformer 25 (FIG. 1) via the cable 14. The twenty-four volt AC powerfrom the transformer 25 is supplied to a rectifier/filter circuit 114(FIG. 11) which supplies twenty-four volt DC power to a power regulationcircuit 116 which may be an ST Microelectronics L78M24CDT-TR regulator.Power from the power regulation circuit 116 is fed to a microcontrollerpower regulator 118 which may be a Microchip MCP 1702T-25021/CBregulator. Power from the power regulation circuit 116 is also fed to awired or wireless sensor communications device 120 that may include, byway of example, an industry standard MMBTA92 for the signal transmitterand an industry standard LM393 comparator for the receiver. Power fromthe power regulation circuit 116 is also fed to a wired or wireless soilmoisture sensor communications device 121 that may include, by way ofexample, an industry standard MMBTA92 for the signal transmitter and anindustry standard LM393 comparator for the receiver.

The microcontroller 108 (FIG. 10) interfaces with the SmartPort(Trademark) connector of the irrigation controller 12 with a combinationinterface/optocoupler 122 which may be provided by an industry standard4N26S device. The microcontroller 108 interfaces with the weatherstation illustrated in FIG. 13. An LCD display 126 is mounted in thehousing 106. Three manually actuable controls in the form of pushbuttons 128 a-c (FIG. 10) are mounted in the housing 106 for enablingthe user to make selections when setting up and modifying the operationof the ET unit 16 in conjunction with information indicated on thedisplay 126 which is facilitated by column and row indicia 130 and 132,respectively, affixed to the housing 106 adjacent the horizontal andvertical margins of the display 126. Row indicia 132 include, from topto bottom, AM, PM, 24 hr, START and END which are printed, painted,molded or otherwise applied to the outer plastic housing such as by asticker. Column indicia 130 are illustrated diagrammatically as A-E inFIG. 10 due to space constraints in the drawing. A-E correspond,respectively, to TIME, TYPE, REGION, NO WATER and WATER+/− withassociated icons which are printed, painted, molded or otherwise appliedto the outer plastic housing 106 such as by a sticker.

FIGS. 12A-12E are flow diagrams illustrating the operation of the standalone ET unit 16. A watering schedule typically includes inputtedparameters such as start times, run times and days to water. The ET unit16 can automatically set the seasonal adjustment of the irrigationcontroller 12 to reduce watering time, or increase watering times,depending on the weather conditions at the time. The ET unit 16 utilizesactual ET data as its basis for making the modifications to the wateringschedules implemented by the irrigation controller 12. However, tosimplify the system and reduce the costs, some of the ET parameters maybe pre-programmed into the ET unit 16 as constants. These constants maybe selected from a group of geographical areas to approximatelyassimilate the local conditions and estimate a maximum ET value. Otherclimatic factors are monitored on a daily basis and are the variables.The variables may include one or more pieces of environmental data suchas temperature, humidity, solar radiation, wind, and rain. In thepreferred embodiment of the present invention, the measured variablesare temperature and solar radiation. The variables and any constants areused by the processor 108 to calculate an estimated ET value. Thisestimated ET value is then used by the ET unit 16 to automatically setthe seasonal adjustment feature of the irrigation controller 12. Theweather station 20 can also include a sensor that indicates a rainevent. A rain event does not affect calculation of an estimated ETvalue. However, it does shut of the irrigation during, and for a periodof time following, the rain event as a further conservation measure.

The user can modify the run and cycle times for individual stations inthe usual manner in the irrigation controller 12. As an example, if onestation is watering too much, but all of the other stations are wateringthe correct amount, the user can easily reduce the run time of thatparticular station and balance the system out. Then the ET unit 16continues modifying the watering schedules executed by the irrigationcontroller 12 on a global basis as a percentage of run time, based onthe calculated estimated ET value. Irrigation controllers can be used tocontrol landscape lighting and other non-irrigation devices such asdecorative water fountains. The controller 12 may have features in itsuch that the ET unit 16 only modifies the watering schedules of theirrigation controller 12.

One of the difficulties with conventional weather-based controllers isattributable to the difficulty of fine-tuning the weather data beingreceived. The environmental sensors may not always be able to be placedin an optimum location on the irrigation site. As an example, a solarradiation sensor may be placed in an area that receives late afternoonshade. This will result in the calculation of an abnormally lowestimated ET value. The entire irrigation site may receive too littlewater and the plant material may become stressed from too little waterif the watering schedules are based on an abnormally low estimated ET.If a conventional ET based irrigation controller receives input fromsuch an incorrectly located solar radiation sensor, the user can attemptto compensate by increasing the run times for each zone by modifyingprecipitation rates to compensate for the error. This is cumbersome andmakes it difficult and frustrating for the user to adjust a conventionalET based irrigation controller for optimum watering.

An advantage of the present invention is the ability to globally modifythe watering schedules of the stand alone irrigation controller 12 tocompensate for this type of condition. If at any time the user realizesthat the property is receiving too little water, the user can simplymanually change an overall watering adjustment feature. The overallwatering adjustment feature is implemented as a simple plus or minuscontrol via actuation of an assigned pair of the push buttons 128 a-c.This changes the reference point of the ET calculation either up ordown. After this adjustment is made, the ET adjustment executed by theET unit 16 references the new setting and then compensates for underwatering that would otherwise occur. Likewise, if the overall wateringis too much for the irrigation site, the user can simply adjust theoverall watering adjustment feature down and create a new lowerreference for the automatic ET based adjustments. The overall wateringadjustment feature makes it easy for the user to fine-tune the system tothe particular requirements of the irrigation site. The overall wateringadjustment feature can be indicated by showing “global adjustment,” or“more/less, water+/−,” or similar naming conventions.

The overall watering adjustment feature of the ET unit 16 directlyalters the station run times executed by the irrigation controller 12.This adjustment modifies the estimated maximum expected ET setting,which is a constant that is used in the calculating the seasonal adjustvalue. When the user makes overall watering adjustments by pressing plusor minus push buttons on the ET unit 16, this directly affects the ETvalue that is used to reset the seasonal adjustment in the hostcontroller 12. In calculating the estimated ET, the microcontroller 108in the ET unit 16 uses only select data points as variables (temperatureand solar radiation) and uses other data points that may consist ofpre-programmed constants, and/or data entered by the user that definessome one or more constants of the site. Estimated ET is calculated usingthe Penman-Monteith formula, taking into account geographical data forpeak estimated summer ET.

Another feature provided by the ET 16 is an automatic shutdown featurefor irrigation that overrides any scheduled run times. There are severaltimes when this is important. A rain sensor in the weather station 20can send signals to the ET unit representing the occurrence of a rainevent. The ET unit 10 will then signal the irrigation controller 12 toshut down and suspend any watering, regardless of any scheduledirrigation running or not running at the time. As another example,during a freeze or near freeze condition, irrigation may produce icethat can be dangerous to people walking or vehicles diving by. Manycities therefore require that irrigation be automatically turned off inthe event of a freeze condition. A temperature sensor in the weatherstation 20 can detect a freeze or near freeze condition and the ET unit16 will signal the irrigation controller 12 to shut down, regardless ofany scheduled irrigation running or not running at the time. As anotherexample, if the user entered irrigation or scheduled irrigation puts toomuch water down for a selected root zone, this can create a hazardouscondition due to water runoff and is also wasteful of water. A soilmoisture sensor attached to the ET unit 10 can detect soil moisturelevels and send signals to the ET unit representing the level ofmoisture 30 present in the soil. The ET unit 10 will then determine fromthese soil moisture levels and user preset limits to selectivelyinhibit, shut down and/or suspend any watering to prevent anoverwatering condition. If the irrigation site experiences very heavyrainfall, and particularly if such rainfall persists for several days,the soil becomes saturated. However a hygroscopic rain sensor will dryout in two or three days, and the irrigation controller will resumeexecuting its pre-programmed watering schedule. Often times the soil isstill sufficiently most to support healthy plant growth and additionalwatering is not needed at this time. The use of a soil moisture sensorto inhibit watering under such circumstances is very advantageous interms of conserving water.

The automatic shutdown feature of the ET unit 10 is also useful ingeographic areas where watering agencies and municipalities imposerestrictions that limit the times when irrigation can occur. The user isable to enter a no-water window into the ET unit 16, which consists ofthe times when irrigation is not allowed to take place. When a no-waterwindow is entered by the user, the ET unit 16 will signal the irrigationcontroller 12 to shut down, regardless of any scheduled irrigationrunning or not running at the time. The ET unit 16 will then allow theirrigation controller 12 to return to its normal run mode after theselected no-water window time has elapsed. The irrigation controller 12may have sensor input terminals, as in the case of the Pro-C irrigationcontroller, which can be used to shut down all watering on receipt of ashutdown command from the ET unit 16.

FIG. 13A is an enlarged vertical cross-section of an embodiment of thestand alone weather station 20 of the system of FIG. 1. The compact andinexpensive weather station 20 measures solar radiation, ambient airtemperature, and detects a rain event. The weather station is aone-piece unit that readily attaches to an exterior side of a buildingstructure, a fence, or a rain gutter. The weather station 20 can be hardwired to the ET unit 16 via cable 18, or the communications between theweather station 20 and the ET unit 16 may take place via wirelesscommunications link 24. The basic construction of the weather station 20is similar to that disclosed in U.S. Pat. No. 6,570,109 granted May 27,2003 to Paul A. Klinefelter et al. entitled QUICK SHUT-OFF EXTENDEDRANGE HYDROSCOPIC RAIN SENSOR FOR IRRIGATION SYSTEMS, and U.S. Pat. No.6,977,351 granted Dec. 20, 2005 to Peter J. Woytowitz entitled MOISTUREABSORPTIVE RAIN SENSOR WITH SEALED POSITION SENSING ELEMENT FORIRRIGATION WATERING PROGRAM INTERRUPT, the entire disclosures of both ofwhich are incorporated herein by reference. Both of the aforementionedU.S. patents are assigned to Hunter Industries, Inc.

The weather station 20 (FIG. 13A) includes an outer injection moldedplastic housing 134 that encloses a pair of moisture absorbing membersin the form of a larger stack 136 of moisture absorbing hygroscopicdiscs and a smaller stack 138 of moisture absorbing hygroscopic discs.These discs are typically made of untreated wood fibers pressed togetherinto a material that resembles cardboard in appearance. One suitablecommercially available hygroscopic material is Kraft Press Board whichis made from cellulose pulp.

The stacks 136 and 138 (FIG. 12A) of hygroscopic discs are supported ona common pivot arm 140 for vertical reciprocal motion relative to avertical shaft 142 that extends through the arm 140. A coil spring 144surrounds the shaft 142 and normally pushes the stack 136 upwardlyagainst stop 146. A torsion spring 147 (FIG. 13B) associated with thepivot axis of the arm 140 lifts the arm 140 and the stack 138 upward toa fixed stop (not illustrated). When rain water enters the housing 134(FIG. 13A) via aperture 150 and funnel 152 the hygroscopic discs of thestacks 136 and 138 absorb water and swell, pushing the arm 140downwardly. A magnet 154 is mounted on one end of the arm 140. Astationary linear Hall effect sensor 156 mounted on a vertically mountedprinted circuit board 158 generates a signal representative of theposition of the magnet 154 that is proportional to the amount of rainwater that has entered the weather station 20. The Hall effect sensor156 may be provided by part number A1395SEHLT-T manufactured by Alegro.The small stack 138 absorbs water quickly via funnel 148 so that a rainevent will be quickly detected. The large stack 136 dries out slowly sothat the rain interrupt signal from the weather station 20 will not beterminated too quickly as the hydroscopic discs dry out. A solarradiation sensor 160 is mounted on one end of the printed circuit board158 and receives solar radiation through a clear plastic dome 162 snapfit over the uppermost part of the housing 134. The solar radiationsensor 160 may be an industry standard PDB-C 131 photodiode with lowcurrent leakage.

The rain sensor including the stacks 136 and 138 of hygroscopic discs,magnet 154 and Hall effect sensor 156 is one form of environmentalsensor that can be used to generate a signal representative of anenvironmental condition on a local irrigation site where the irrigationcontroller 12 is installed. The solar radiation sensor 160 is anotherform of environmental sensor that can generate another signalrepresentative of another environmental condition on the irrigationsite. Those skilled in the art will appreciate that variousenvironmental sensors may be used on the site, alone or in combination,such as a rain sensor, a solar radiation sensor, a wind speed sensor, ahumidity sensor, a freeze sensor, a temperature sensor, and so forth.

FIG. 14 is a block diagram illustrating the electronic circuit of thestand alone weather station 20 that is mounted on the printed circuitboard 158. The solar radiation sensor 160 which may comprise a PDB-C131photodiode that is connected to a Microchip MCP6001T-I/LT transimpedanceamplifier 164 that is in turn connected to a Microchip PIC-16F684-I/SLmicro controller 166. A Microchip MCP9700T-E/LT temperature sensor 168with an ND interface is also connected to the microcontroller 166. Themicrocontroller 166 also receives the output signal from the Hall effectsensor 156. The Hall effect sensor 156 may comprise a MicrochipA1395SEHLT-T Hall effect sensor and interface circuit. Thecommunications interface 170 between the microcontroller 166 and the ETunit 16 may be a hard wire interface, or more preferably, a wirelessinterface that may comprise a Microchip Technology RFPIC675 transmitterand a Maxim MAX1473 receiver. The transmitter sends signalsrepresentative of actual components of ET data across the irrigationsite to the ET unit 16. Power for the hard wired weather station 20 isderived from the communications link to the ET unit 16 and is fed to aninput conditioner 172 which feeds a Microchip MCPI702T-3002E/CB powerregulator 174. The power regulator 174 supplies three volt DC power tothe microcontroller 166. Power for a wireless weather station issupplied by a dedicated battery (not illustrated) installed within theweather station.

FIG. 15 is a flow diagram illustrating the operation of the stand aloneweather station 20 of FIG. 13. Firmware executed by the micro controller166 allows the weather station 20 to perform the logical operationsillustrated in the flow diagram. These include periodic sampling of theoutputs from the solar radiation sensor 162, temperature sensor 168 andHall effect sensor 156, averaging readings, and responding to requestsfor sensor data that are periodically transmitted by the ET unit 16.

The basic construction of the soil moisture sensor 21 may be similar tothat disclosed in U.S. Pat. No. 5,179,347 granted Jan. 12, 1993 toAlfred J. Hawkins entitled ELECTRICAL SENSOR FOR SENSING MOISTURE INSOILS, the entire disclosure of which is incorporated herein byreference. The aforementioned U.S. patent is assigned to IrrometerCompany, Inc., Riverside, Calif.

FIG. 16 is a block diagram illustrating the electronic circuitconnecting to the stand alone soil moisture sensor 21. This functionalblock may be physically located within the ET unit 10. In the preferredembodiment, this functional block is located within a separate injectionmolded plastic housing that interfaces directly with the electrodes. Thesoil moisture sensor is resistance based and measures the current drawwithin the sensor from a constant voltage source. The soil moisturesensor electrodes 160 which are connected to cable 19 are in turnconnected to a buffer 162. This buffer 162 may be an H-bridge bufferincluding industry standard 2N3904/3906 discrete bipolar transistors.The H-bridge is used to periodically switch polarities of the sensorwires. This is to prevent galvanic corrosion from occurring in theburied sections of the wire leading out to the electrodes.

A surge protection circuit 164 is also connected to the buffer that mayconsist of metal oxide varistors and on board spark gaps connected toeach output of the H-bridge. The buffer 162 is in turn connected to aMicrochip PIC18F684-I/SL microcontroller 166.

The communications interface 168 between the microcontroller 166 and theET unit 10 may be a hard wire interface, or more preferably, a wirelessinterface that may comprise a Microchip Technology RFPIC675 transmitterand a Maxim MAX1473 receiver. The transmitter sends signalsrepresentative of actual components of soil moisture data within thesoil at the root zone to the ET unit 10. Power for the hard wired soilmoisture sensor 21 is derived from the communications link to the ETunit 10 and is fed to an input conditioner 170 which feeds a MicrochipMCP1702T-3002E/CB power regulator 7. The power regulator 172 supplies 15V DC power to the power regulator 174. Power regulator 174 suppliesthree volt DC power to the micro controller 166. When there is awireless connection, power is supplied by a dedicated battery (notillustrated) installed within the soil moisture sensor.

FIG. 17 is a flow diagram illustrating the operation of the stand alonesoil moisture sensor 21 of FIG. 1. Firmware executed by themicrocontroller 166 allows the soil moisture sensor 21 to perform thelogical operations illustrated in the flow diagram. These includeperiodic sampling of the output from the soil moisture sensor 21,switching H-bridge energizing polarities, and responding to requests forsensor data that are periodically transmitted by the ET unit 10.

The ET unit 16 of the present invention utilizes the watering programset up procedures that the installers, maintenance personnel andhomeowners are already accustomed to using. Start times, station runtimes, and days-to-water are manually entered into the irrigationcontroller 12. The user also selects from one of a group of geographicalregions in the ET unit 16. The ET unit 16 then automatically takes oversetting of the seasonal adjustment feature of the irrigation controller12 on a regular basis. Instead of a user changing that feature severaltimes per year, the ET unit 16 sets that seasonal adjustment dailydepending on current weather conditions gathered on site. Furthermore,the ET unit 16 shuts down any scheduled watering by the irrigationcontroller 12 in response to a rain event or a freeze event, and whenthere is a scheduled no-water window. Cost savings are achieved sinceonly a small number of the weather parameters need to be measured. Thesevariables are then used with pre-programmed constants to calculate anestimated ET value. This approach allows for cost savings since thestand alone weather station 20 need not have more than a solar radiationsensor, a temperature sensor and a rain sensor.

The present invention also provides a unique method of controlling aplurality of valves on an irrigation site. The method includes the stepsof selecting and/or creating a watering schedule, storing the wateringschedule and generating a signal representative of an environmentalcondition on an irrigation site. The method also includes the steps ofcalculating an estimated ET value based at least in part on the signaland selectively turning a plurality of valves located on the irrigationsite ON and OFF in accordance with the watering schedule. The methodfurther includes step of automatically modifying the watering schedulebased on the estimated ET value using a seasonal adjust algorithm tothereby conserve water while maintaining the health of plants on theirrigation site. The method further includes the step of inhibitingwatering if the moisture sensed by a soil moisture sensor is above apredetermined threshold. Optionally, the method of present invention mayfurther include the step of inputting an overall watering adjustment andautomatically modifying the watering schedule through the seasonaladjust algorithm based on the estimated ET value as increased ordecreased by the inputted overall watering adjustment.

While an embodiment of an irrigation system comprising a stand alone ETunit connected to stand alone irrigation controller and linked to aseparate stand alone weather station has been described in detail,persons skilled in the art will appreciate that the present inventioncan be modified in arrangement and detail. The calculated ET values maybe down loaded to a controller that changes the irrigation schedule ofeach individual station rather than changing the seasonal adjustfeature. The features and functionality described could be provided bycombining the irrigation controller and the ET unit into a singleintegrated unit 212 (FIG. 18), in which case a single microcontrollermay replace the microcontrollers 40 and 108. Alternatively, the ET unitcould be packaged in an ET module designed for removable insertion intoa receptacle in a stand alone irrigation controller. The receptacle maybe on a housing, a backplane, or in a control panel of the irrigationcontroller. The module may be installed in the housing of the irrigationcontroller and hard wired to the control unit, or the electricalconnections may be made through the receptacle. The soil moisture sensor21 need not be the patented Hawkins type specifically identified herein.A wide variety of commercially available soil moisture sensors could beused that include electrodes, capacitive plates, expanding members,switches, energy degrading technology, and so forth. The moisturethreshold setting may be an integral part of the soil moisture sensor.The sensor may supply a simple on off signal instead of a variablesignal so there is no threshold setting at the controller. Examples ofother soil moistures include United States Patent Application number2008/0202220 of Schmidt entitled DEVICE FOR MEASURING THERMAL PROPERTIESIN A MEDIUM AND METHOD FOR DETERMINING THE MOISTURE CONTENT IN THEMEDIUM published Aug. 28, 2008; United States Patent Application number2008/0202219 of Schmidt entitled DEVICE FOR USING WITH A SENSOR FORIMPROVING ACCURACY, AND SENSOR WITH AN IMPROVED ACCURACY published Aug.28, 2008; United States Patent Application number 2010/0277185 of Hughesentitled SOIL MOISTURE SENSOR published Nov. 4, 2010; United StatesPatent Application number 2010/0251807 of Morton entitled MOISTUREMONITORING DEVICE AND METHOD published Oct. 7, 2010. The entiredisclosures of the aforementioned Schmidt, Hughes and Morton patentapplications are hereby incorporated by reference. Therefore, theprotection afforded the subject invention should only be limited inaccordance with the scope of the following claims.

What is claimed is:
 1. An irrigation system comprising: a stand aloneweather station including at least one environmental sensor configuredto detect an environmental condition of an irrigation site; a soilmoisture sensor configured to detect a level of soil moisture; and anirrigation controller operatively in communication with the soilmoisture sensor and the stand alone weather station, the irrigationcontroller comprising a plurality of user inputs that enable a user toenter a watering schedule including a run time and to manually adjust apercentage adjustment value of a percentage adjustment feature, acomputer processor operatively connected to the plurality of userinputs, a memory operatively connected to the computer processor, and aplurality of switches operatively connected to the computer processor toturn a power signal ON and OFF to a plurality of valves that deliverwater to a plurality of sprinklers, wherein programming stored in thememory accepts input from the user via the plurality of user inputs toimplement the watering schedule such that during said run time, thecomputer processor operates ones of the plurality of switches to deliverwater to ones of the sprinklers to irrigate an irrigation site and toimplement said percentage adjustment feature to change the run time ofthe watering schedule by the percentage adjustment value, wherein theprogramming further automatically increases or decreases said percentageadjustment value in response to the environmental condition, and whereinthe computer processor automatically inhibits irrigation when the levelof soil moisture is above a threshold.
 2. The irrigation system of claim1 wherein the irrigation controller comprises a stand alone irrigationcontroller different from the soil moisture sensor and the stand aloneweather station.
 3. The irrigation system of claim 1 wherein the standalone weather station is located at the irrigation site and comprises asolar radiation sensor configured to detect solar radiation and atemperature sensor configured to detect temperature, and wherein theenvironmental condition comprises the solar radiation and thetemperature.
 4. The irrigation system of claim 3 wherein the irrigationcontroller calculates an irrigation value based at least in part on thesolar radiation, the temperature, and at least one constant.
 5. Theirrigation system of claim 4 wherein the watering schedule is modifiedon a global basis as a percentage of the run time based at least in parton the irrigation value.
 6. The irrigation system of claim 4 wherein theat least one constant is based at least in part on peak summerirrigation of the irrigation site.
 7. The irrigation system of claim 4wherein the irrigation controller determines an irrigation adjustmentvalue based at least in part on the irrigation value.
 8. The irrigationcontroller of claim 7 wherein the programming automatically increases ordecreases said percentage adjustment value by said irrigation adjustmentvalue.
 9. The irrigation system of claim 8 wherein the at least oneconstant comprises a reference point used in calculating the irrigationvalue.
 10. The irrigation system of claim 9 wherein the plurality ofuser inputs further enables the user to adjust the reference point. 11.An irrigation system comprising: a plurality of user inputs that enablea user to enter a watering schedule including a run time and to manuallyadjust a percentage adjustment value of a percentage adjustment feature;a computer processor operatively connected to the plurality of userinputs and to a memory configured to store the watering schedule; aplurality of switches operatively connected to the computer processorand configured to turn a power signal ON and OFF to a plurality ofvalves that deliver water to a plurality of sprinklers; a first sensorconfigured to generate a first signal representative of an environmentalcondition; a second sensor configured to generate a second signalrepresentative of a soil moisture level; and programming stored in thememory to accept input from the user via the plurality of user inputs toimplement the watering schedule such that during said run time thecomputer processor operates ones of the switches to turn the powersignal ON to one or more of the plurality of valves thereby deliveringthe water to ones of the sprinklers to irrigate an irrigation site andto implement said percentage adjustment feature to increase or decreasethe run time of the watering schedule by the percentage adjustmentvalue, the programming automatically increasing or decreasing saidpercentage adjustment value in response to the first signalrepresentative of the environmental condition, the computer processorautomatically inhibiting irrigation when the soil moisture levelindicated by the second signal is above a threshold.
 12. The irrigationsystem of claim 11 wherein the first sensor comprises a solar radiationsensor configured to detect solar radiation and a temperature sensorconfigured to detect temperature, and wherein the environmentalcondition comprises the solar radiation and the temperature of anirrigation site.
 13. The irrigation system of claim 12 wherein the firstsensor further comprises a rain sensor configured to detect a rainevent, and wherein the computer processor automatically inhibitsirrigation based at least in part on the rain event.
 14. The irrigationsystem of claim 12 wherein the temperature sensor is further configuredto detect a freeze event and wherein the computer processorautomatically inhibits irrigation based at least in part on the freezeevent.
 15. The irrigation system of claim 11 wherein the plurality ofuser inputs further enable the user to enter a no water window, andwherein the computer processor automatically inhibits irrigation basedat least in part on the no water window.
 16. A method of controlling aplurality of valves on an irrigation site, the method comprising:receiving from a plurality of user inputs a watering schedule includinga run time and a percentage adjustment value of a percentage adjustmentfeature configured to change the run time of the watering schedule bysaid percentage adjustment value; receiving a first signalrepresentative of an environmental condition on the irrigation site;receiving a second signal representative of a soil moisture level;selectively turning a power signal ON to a plurality of valves thatdeliver water to a plurality of sprinklers located on an irrigation siteaccording to the watering schedule; implementing said percentageadjustment feature to increase or decrease the run time of the wateringschedule by the percentage adjustment value; automatically increasing ordecreasing said percentage adjustment value in response to the firstsignal representative of the environmental condition; and automaticallyinhibiting irrigation when the soil moisture level indicated by thesecond signal is above a threshold.
 17. The method of claim 16 furthercomprising receiving from the plurality of user inputs the threshold toprevent the irrigation when the second signal from a soil moisturesensor exceeds the threshold.
 18. The method of claim 16 furthercomprising calculating an irrigation value based at least in part on thefirst signal representative of the environmental condition on theirrigation site and a constant comprising peak summer irrigation for theirrigation site.
 19. The method of claim 18 further comprisingdetermining an irrigation adjustment value based at least in part on theirrigation value.
 20. The method of claim 19 further comprisingautomatically increasing or decreasing said percentage adjustment valueby the irrigation adjustment value.